Production process for refined hydrogen iodide

Abstract

A process for producing refined hydrogen iodide having organic components of 0.2 ppm by volume or less and water of 0.1 ppm by volume or less by contacting crude hydrogen iodide with a zeolite is disclosed. Crude hydrogen iodide is obtained by reducing iodine with a hydrogenated naphthalene, wherein all of the iodine is dissolved in advance in a portion of the hydrogenated naphthalene to prepare an iodine solution, and the reaction is carried out while adding continuously or intermittently the iodine solution to the balance of the hydrogenated naphthalene. The same operation may be repeated in succession using unreacted hydrogenated naphthalene and fresh iodide. The zeolite is contacted in advance with crude hydrogen iodide, the amount of which is at least +E,fra 1/3+EE (weight ratio) relative to the amount of the zeolite, to convert impurities of sulfur components contained in the zeolite to hydrogen sulfide, thereby removing the sulfur components. Further, an activated carbon may be combined with the zeolite at the rear stage thereof.

What is claimed is: 
     
       1. A process for producing refined hydrogen iodide, said process comprising the steps of: (a) contacting a zeolite containing sulfur impurities therein with crude hydrogen iodide at conditions effective to convert said sulfur impurities to hydrogen sulfide including a temperature of 50° C. or higher to remove said sulfur impurities from said zeolite; and   (b) contacting additional crude hydrogen iodide with the zeolite from step (a) in a gaseous phase at condition effective to remove impurities in said additional crude hydrogen iodide to produce refined hydrogen iodide which contains 1 ppm by volume or less of hydrogen sulfide.   
     
     
       2. A process for producing refined hydrogen iodide according to claim 1, wherein the crude hydrogen iodide is obtained by dissolving iodine in hydrogenated naphthalene to form an iodine solution, and continuously or intermittently adding the iodide solution to additional hydrogenated naphthalene at conditions effective to react the iodine with the hydrogenated naphthalene to form crude hydrogen iodide. 
     
     
       3. A process for producing refined hydrogen iodide according to claim 2, further comprising (c) dividing liquid remaining after the reaction of iodide with hydrogenated naphthalene into a first portion and a second portion, (d) dissolving additional iodine in the first portion to form a new iodide solution, (e) adding the new iodide solution continuously or intermittently to the second portion at conditions effective to react the additional iodide with the hydrogenated naphthalene to form additional crude hydrogen iodide, and (f) repeating steps (c)-(e). 
     
     
       4. A process for producing refined hydrogen iodide according to claim 1, wherein the amount of the crude hydrogen iodide used to remove the sulfur impurities contained in the zeolite is at least 1/3 of the weight of the zeolite. 
     
     
       5. A process for producing refined hydrogen iodide according to claim 1, wherein the zeolite is an A type zeolite or a mordenite type zeolite. 
     
     
       6. A process for producing refined hydrogen iodide according to claim 5, wherein said A type zeolite has an average pore diameter of 3 angstrom, 4 angstrom, or 5 angstrom. 
     
     
       7. A process for producing refined hydrogen iodide according to claim 6, wherein said A type zeolite has an average pore diameter of 4 angstrom. 
     
     
       8. A process for producing refined hydrogen iodide according to claim 5, wherein the refined hydrogen iodide contains 1 ppm by volume or less of water, and 1 ppm by volume or less of organic substances. 
     
     
       9. A process for producing refined hydrogen iodide according to claim 6, wherein the refined hydrogen iodide contains 0.5 ppm by volume or less of organic substances. 
     
     
       10. A process for producing refined hydrogen iodide according to claim 7, wherein the refined hydrogen iodide contains 0.1 ppm by volume or less of water. 
     
     
       11. A process for producing refined hydrogen iodide according to claim 6, wherein the zeolite is used in combination with an activated carbon, and the crude hydrogen iodide is contacted with the combination of the zeolite and the activated carbon at conditions effective to produce a refined hydrogen iodide containing 0.2 ppm by volume or less of organic substances. 
     
     
       12. A process for producing refined hydrogen iodide according to claim 11, wherein the activated carbon is first contacted with crude hydrogen iodide at conditions effective to convert sulfur impurities contained in the activated carbon to hydrogen sulfide to remove said sulfur impurities from the activated carbon. 
     
     
       13. A process for producing refined hydrogen iodide according to claim 12, wherein the amount of the crude hydrogen iodide used to remove the sulfur impurities contained in the activated carbon is at least 1/3 of the weight of the activated carbon. 
     
     
       14. A process for producing refined hydrogen iodide according to claim 2, wherein the amount of the crude hydrogen iodide used to remove the sulfur impurities contained in the zeolite is at least 1/3 of the weight of the zeolite. 
     
     
       15. A process for producing refined hydrogen iodide according to claim 2, wherein the zeolite is an A type zeolite or a mordenite type zeolite. 
     
     
       16. A process for producing refined hydrogen iodide according to claim 15, wherein said A type zeolite has an average pore diameter of 3 angstrom, 4 angstrom, or 5 angstrom. 
     
     
       17. A process for producing refined hydrogen iodide according to claim 16, wherein said A type zeolite has an average pore diameter of 4 angstrom. 
     
     
       18. A process for producing refined hydrogen iodide according to claim 15, wherein the refined hydrogen iodide contains 1 ppm by volume or less of water, and 1 ppm by volume or less of organic substances. 
     
     
       19. A process for producing refined hydrogen iodide according to claim 16, wherein the refined hydrogen iodide contains 0.5 ppm by volume or less of organic substances. 
     
     
       20. A process for producing refined hydrogen iodide according to claim 17, wherein the refined hydrogen iodide contains 0.1 ppm by volume or less of water. 
     
     
       21. A process for producing refined hydrogen iodide according to claim 16, wherein the zeolite is used in combination with an activated carbon, and the crude hydrogen iodide is contacted with the combination of the zeolite and the activated carbon at conditions effective to produce a refined hydrogen iodide containing 0.2 ppm by volume or less of organic substances. 
     
     
       22. A process for producing refined hydrogen iodide according to claim 21, wherein the activated carbon is first contacted with crude hydrogen iodide at conditions effective to convert sulfur impurities contained in the activated carbon to hydrogen sulfide to remove said sulfur impurities from the activated carbon. 
     
     
       23. A process for producing refined hydrogen iodide according to claim 20, wherein the amount of the crude hydrogen iodide used to remove the sulfur impurities contained in the activated carbon is at least 1/3 of the weight of the activated carbon.